1. Field of the Invention
This invention relates to a feeding mechanism. More particularly, this invention relates to a feeding mechanism provided with rollers supported by one-way bearings so as to deskew the media or paper without wrinkling.
2. Description of Prior Art
Office machines, such as printers, scanners, copiers, generally include a feeding mechanism for feeding the media (or paper) into the office machines sheet by sheet in sequential order. Traditionally, the feeding mechanism comprises an SP-roller (separation-paper roller) and a feeding roller. The SP-roller picks up the media (or paper) and moves the media towards the feeding roller. The feeding roller rotates in a direction opposite to the feeding direction of the media for a period of time such that the media can be deskewed. After the deskew period, both the SP-roller and the feeding roller will change their rotating directions such that the feeding roller rotates in the feeding direction while the SP-roller rotates in a direction opposite the feeding direction. By this means, media will be stretched and moved into the office machine for further processing, such as printing or scanning.
However, the deskewing operation generally causes the media to wrinkle on the leading edge, and in the worse case the media fails to be fed by the feeding roller. The stretch operation also interferes with the forward movement of the media, and in worse cases the media is torn.
The present invention modifies the operation of the SP-roller, the feeding roller, and the corresponding mechanism to improve the performance of the feeding mechanism and overcome the above problems. According to one embodiment of the present invention, the feeding mechanism includes a base provided with a first surface, a second surface, a first roller, a second roller, a first one-way bearing supporting the first roller, a second one-way bearing supporting the second roller, a cam gear and a stopper. The embodiment uses one-way bearings to control the rotation of the SP-roller and the feeding roller. During the deskew operation, the feeding roller does not rotate when the media is moved ahead by the SP-roller. During the stretching operation, the SP-roller is idled and can freely rotate when the media is moved further ahead by the feeding roller. Accordingly, the media can be transmitted smoothly from the paper tray into the office machine.